Well in Gokaiger's "Legend war" the dead did come back for a brief time.
And in a bit of related news
There was an interview that said Toei would film a new legend war excluding the post Zyuranger teams for Saban to use when Gokaiger is adapted
-Power Rangers 20th Anniversary
-They talk about Power Rangers' forthcoming 20th Anniversary this year. This is the interview where talked about making a version of the Legend War with only the post-Zyu teams.
If someone knows Japanese can you provide confirmation on what was translated?
This could be like Toei providing additional footage back in 1992. The "Zyu 2" footage that made up season 2 of Power Rangers.
Zyuranger had already ended but Saban requested some scenes be filmed by Toei so he could use it for MMPR season 2.
This could be like "Gokaiger 2" Only half of the post zyuranger teams will be excluded